The wide spread application of conventional geo polymer is presently hindering all over the world due to its workability aspect. Since a) the raw material, b) the process of making, and c) reaction mechanism involved in geopolymeric system are all together different than in convention cement making system and therefore the use of conventional super plasticizer and plasticizer does not hold good for the geopolymeric system because the super plasticizer are attacked by alkaline solutions and degrade rapidly. Researchers have found that the conventional super plasticizer do help to some extend but at the cost of compromising other functional properties of the geopolymeric system. Unlike, conventional cement concrete system, the geopolymeric system seriously suffers from the inherent viscous characteristics of the raw materials and the reaction product formed, i.e., geopolymeric gel necessary for making conventional geopolymeric system.
The conventional geopolymeric system is made using solution of a) sodium hydroxide b) sodium meta silicate which are viscous in nature. Further, the geopolymeric reaction of fly ash with alkaline activator solution prepared using NaOH and sodium meta silicate solution leads to the formation of geopolymeric gel which is also a highly viscous material. The viscous nature of geopolymeric gel is further gets enhanced due to the presence of un reacted solution of NaOH in the matrix of geopolymeric gel. Thus, overall the viscous characteristics in geopolymeric system are responsible for observed negligible workability of geopolymeric cement concrete system and which limits its broad application spectrum.
To improve the workability of geo polymeric system there is an urgent need to develop new advanced multifunctional material capable of addressing viscosity issues along with further improving the techno economic aspect of the geo polymeric system and thus significantly widening its application spectrum. In view of above a novel, process for making multifunctional material for geo polymeric system and the process thereof has been developed. The multifunctional material has been developed by a novel process comprising of digestion of siliceous agricultural waste, i.e., Rice husk with aqueous alkaline materials involving simultaneous and synergistic chemical reactions among the various constituents of rice husk, aqueous alkaline compounds and optionally added CTAB to obtain in-situ synthesis of desired nano-sized multi functional agents lignin, hemicelluloses, cellulose, sodium silicate necessary for addressing the issue of workability and also improving the engineering properties of geopolymeric system and ultimately leading to the techno-economic feasibility of geopolymeric system for broad application spectrum.
The use of developed multifunctional materials apart from addressing the issue of workability also enables:    1) obviating the need of one of the important and costly raw material that is sodium silicate otherwise necessarily required to be added externally.    2) Providing the hemicelluloses which is responsible for improving the mechanical properties, modifying the viscosity and also acts as a gelling agent.    3) Providing the cellulose which is also responsible for improving the mechanical properties, modifying the viscosity and also acts as a binding agent.    4) The alkaline rice lignin with a high hydroxyl group content possess excellent thermal stability and therefore it is useful for providing heat resistant properties to the developed geopolymeric matrix.
Reference may be made to article “Effect of Plasticizer and super plasticizer on workability of fly ash based geopolymer concrete” by A. I Laskar et. al. in Proceedings of International conference on Advanced in Architecture and Civil Engineering (AARCV 2012), 2012 wherein an attempt has been made to study variation of workability of fly ash based geopolymer concrete with the variation of lignin based plasticizer and poly carboxylic ether based super plasticizer. The drawback of the process that the use of plasticizers critically depends upon molarity of alkaline solutions used in geopolymeric system and since the conventional super plasticizers does not withstand high alkaline environment and also are not biodegradable.
Reference may be made to article “Efficacy of Available Super plasticizers on Geopolymers” by B. Nematollahi et al. in research journal of Applied Sciences, Engineering and Technology 7(7); 1278-1282,2014 wherein a state of the art review of the effect of different SPs on slag and fly ash based geopolymers has been reported. The drawback of the process is that the super plasticizers are attacked by alkaline solutions and degrade rapidly and also the conventional SPs are not biodegradable.
Although researchers have reported, that the use of super plasticizers used in conventional cement concrete system do not help in totality when they are used in Geopolymeric system. Further, no literature is available in making a novel multifunctional material useful for geopolymeric system for addressing its workability issues.
Reference may be made to Indian patent application 156/DEL/2014, wherein geopolymeric material is prepared in solid form using rice husk, NaOH, fly ash and optionally sodium silicate.
Further, from the reported prior it is found that development of multifunctional material useful for geopolymeric system for addressing its workability issues has not been pursued seriously. From the hitherto reported prior art and based on the drawbacks of the known processes, the various issues that need to be addressed and problems to be solved specially of workability concerns of conventional geopolymeric system need to be addressed urgently to widen the application spectrum of geopolymeric system.